Software

How to add an email signing certificate for messages in the iOS Mail app

There are so many fake emails being sent that it's more important than ever to prove your emails are coming from you. Here's how to add an email signing certificate to your iOS Mail app.

Email signing certificates can prove that emails really did come from you; these certificates can also be used to encrypt the emails you send. Follow the steps in this tutorial to learn how to create a certificate, import it into any version of iOS, assign it to an email account, and then send a message using your certificate.

SEE: Mobile device computing policy (Tech Pro Research)

How to create an email certificate

Many corporate email accounts use certificates to verify users sending the emails and provide encryption for messages sent inside of the company; however, if you don't already have an email certificate, you can easily generate one using Comodo's free secure email certificate.

After filling out the form and confirming your email address, you'll be given a certificate file that you can download to your computer. Download the file and keep it in a safe place for use in the next step. The certificate that is generated is valid for one year, after which this process will need to be completed again to generate a new certificate that's valid for the following year.

SEE: Special report: Cybersecurity in an IoT and mobile world (free PDF) (TechRepublic)

How to import an email certificate

To import an email certificate to an iOS device, follow these steps.

  1. Email yourself the certificate file (a .p12 file).
  2. Open the email on your iOS device.
  3. Tap the .p12 certificate file in the attachments list of the email.
  4. iOS will prompt you to install the certificate. Tap Install, and then enter your iOS password.

Note: You can optionally use AirDrop from a macOS device to iOS to AirDrop the .p12 file, which will prompt you to install the certificate.

Either action will cause the certificate to be installed in Settings.app | General | Profiles & Device Management | Configuration Profiles.

How to assign a certificate to an email account

To assign a certificate to an email account and start sending signed emails, perform these steps.

  1. Open Settings.app.
  2. Navigate to Accounts & Passwords.
  3. Select the email account you wish to configure.
  4. Select Account | Advanced.
  5. Locate the S/MIME section and enable the toggle for S/MIME.
  6. Select the Sign section, and enable the toggle for Sign, selecting the certificate you imported from the certificates list (Figure A).

Figure A

emailsigningfigureaedited.jpg

You can tap the "i" to the right of the certificate name in the list to get more details about it, such as the expiration date.


If the certificate doesn't appear in this listing, it's possible the certificate expired, wasn't properly imported, or wasn't for the email address you're attempting to assign it to.

SEE: Secure your iPhone and iPad: Change these iOS 11 privacy and security settings now (ZDNet)

How to send a signed email message

To send a signed message, just follow the same flow that you've always used for sending a signed message. By default, if an S/MIME has been selected, iOS Mail will automatically sign the message. If you have a certificate that supports encryption, you'll be able to tap the Lock that will appear when entering a "To" address in the compose view—this will cause the message to be encrypted to the sender.

Note: This certificate is only valid inside of the Apple Mail app and doesn't work with other third-party apps; you'll need to follow the third-party app setup to determine if you can import a certificate.

Also see

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Image: Getty Images/iStockphoto, wutwhanfoto

About Cory Bohon

Cory Bohon is an indie developer specializing in iOS and OS X development. He runs a software company called Cocoa App and is also a developer at MartianCraft. He was introduced to technology at an early age and has been writing about his favorite te...

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